The present invention relates to a majority decision device adapted for making a majority decision with respect to repeatedly and serially received data words.
In mobile telecommunication and similar wireless communications, the accurate reception of data frequently becomes difficult due to various phenomena such as fading, etc. To overcome this difficulty, it has been conventional to transmit the same data word repeatedly and, on the receiver side, to make a majority decision on the received group of data words.
In a conventional system for effecting majority decision, the total data words received during the repeated cycles are stored in a shift register or the like, and the corresponding bits in the respective data words are taken out concurrently to be judged whether it is "0" or "1" by means of a decision circuit. However, such prior art system involves many problems such that the capacity required for the shift register increases in proportion to the repetition number of the data word transmission, and that according to the increase of the repetition number, the expansion of the decision circuit is hardly feasible.
Such a conventional decision circuit in the prior art is described in "5-Input Majority Gates" on page 7-242 of "THE SEMICONDUCTOR DATA LIBRARY, SERIES A, VOLUME V" published in 1957 by MOTOROLA INC.